1. Field of the Invention
This invention relates generally to an industrial process, such as a semiconductor manufacturing process, a photographic process or a chemical process. More particularly, the invention relates to detecting and classifying faults in the industrial process based on calculating distances between data points.
2. Description of the Related Art
There is a constant drive to increase the quality, reliability, and throughput of industrial processes, which may include, but are not limited to, semiconductor manufacturing processes, photography processes, and/or chemical processes. In an effort to improve the overall process, the trend has been to measure and record more process variables than before, variables such as temperature, pressure, and concentrations of gas mixtures or chemical agents, and to use those measured variables in controlling the process.
The amount of data that is collected for a given process increases as a greater number of variables are measured (or monitored) and as the frequency of those measurements is increased. For some processes, particularly in the chemical field, more than a hundred variables may be monitored at any given time, and, as such, large amounts of data that are associated with these processes may be collected for later analysis.
Analyzing large amounts of collected data, however, poses a challenge because of the processing power or resources that are required to process the data, possibly within a specified amount of time. Because of limited processing capabilities and/or time constraints, users often times choose and analyze only a selective subset of variables that are considered to be more important, while ignoring the other variables. However, excluding measured variables that are not considered to be desirable by users may result in the loss of valuable information, particularly from the standpoint of fault detection and classification. Relying on incomplete data may result in false fault detection or misclassification. As a result, processing efficiencies may be reduced.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.